Thin film microwave voltage controlled oscillator

Claim 1

A thin film microwave voltage controlled oscillator having an octave tuning bandwidth comprising: a ground plane, a dielectric substrate carried by said ground plane; a transistor having emitter, collector and base terminals mounted on said substrate; a capacitor connected between said emitter and collector terminals, an emitter bias circuit connected to said emitter terminal, said bias circuit including serially connected thin film resistors and a spiral transmission line section connected between the emitter and the ground plane and a bypass capacitor connected between said series circuit and said ground plane; a base circuit connected to said base terminal, said base bias circuit including a voltage divider comprising thin film resistors, and means including a spiral transmission line section connected between said base and the voltage divider and a bypass capacitor connected between the voltage divider and the ground plane; a varactor supported on said substrate, said varactor having one terminal serially coupled to said base terminal through a blocking capacitor; means including a serial spiral transmission line for applying a tuning voltage to the one terminal of said varactor; and an output circuit connected between the other terminal of said varactor and the ground plane, said output circuit forming an output coupling means for coupling the oscillator to an associated load, said thin film resistors being tantalum nitride films supported on said substrate and said spiral transmission lines and resistors being formed by selective etching of thin film layers formed on the dielectric substrate said layers comprising in order a tantalum nitride layer, a conductive barrier layer and a conductive surface layer.